Do you have separate databases for PHP-Nuke and phpBB2? Sometimes if you have separate databases and have the same username and password for both, the convertor will not work. Either place the PHP-Nuke tables into the phpBB2 database or create a unique user and password for the PHP-Nuke database.

EDIT: Looks like the table is named "bbprivmsgs", not privmsgs as the script thinks. Let me take a look before anyone looks into this.
Hello, I am very happy to have found this script! Thanks for keeping it alive!

I have php-nuke 7.8 and phpbb 2.0.23 in the same database. When I run the script it does not go to completion and only a few tables are copied. There is no error message displayed. Is there any way to see why the conversion stopped?

Query
INSERT INTO phpbb_forums (forum_id,cat_id,forum_name,forum_desc,forum_status,forum_order,forum_posts,forum_topics,forum_last_post_id,forum_notify,prune_next,prune_enable,auth_view,auth_read,auth_post,auth_reply,auth_edit,auth_delete,auth_sticky,auth_announce,auth_globalannounce,auth_vote,auth_pollcreate,auth_attachments,auth_download) values ('2','1','PBJ Team General Board','Welcome to the PBJ Team Forum! Have a question or comment for the team, place it here.','0','20','734','82','4280','1','','0','0','0','1','1','1','3','3','3','3','1','1','1','1')

It appears i was using an older version of the converter. Just tried the link you gave me and it works perfect. Thanks / Only using phpbb2 as the theme i need to use for it was designed for phpbb2 and cant confirm it will work for phpbb3